Antemortem detection of Mycobacterium bovis in nasal swabs from African rhinoceros

Mycobacterium bovis (M. bovis) infection has been identified in black (Diceros bicornis) and white (Ceratotherium simum) rhinoceros populations in Kruger National Park, South Africa. However, it is unknown whether M. bovis infected rhinoceros, like humans and cattle, can shed mycobacteria in respiratory secretions. Limited studies have suggested that rhinoceros with subclinical M. bovis infection may present minimal risk for transmission. However, recent advances that have improved detection of Mycobacterium tuberculosis complex (MTBC) members in paucibacillary samples warranted further investigation of rhinoceros secretions. In this pilot study, nasal swab samples from 75 rhinoceros with defined infection status based on M. bovis antigen-specific interferon gamma release assay (IGRA) results were analysed by GeneXpert MTB/RIF Ultra, BACTEC MGIT and TiKa-MGIT culture. Following culture, speciation was done using targeted PCRs followed by Sanger sequencing for mycobacterial species identification, and a region of difference (RD) 4 PCR. Using these techniques, MTBC was detected in secretions from 14/64 IGRA positive rhinoceros, with viable M. bovis having been isolated in 11 cases, but not in any IGRA negative rhinoceros (n = 11). This finding suggests the possibility that MTBC/M. bovis-infected rhinoceros may be a source of infection for other susceptible animals sharing the environment.

Reduced capability of refrigerated white rhinoceros whole blood to produce interferon-gamma upon mitogen stimulation

Ante-mortem surveillance for Mycobacterium bovis (M. bovis) infection in the Kruger National Park (KNP) rhinoceros population currently relies on results from the QuantiFERON-TB Gold (In-Tube) Plus (QFT)-interferon gamma (IFN-γ) release assay (IGRA). However, same-day processing of rhinoceros blood samples for this test is a logistical challenge. Therefore, a pilot study was performed to compare mitogen-stimulated and unstimulated IFN-γ concentrations in plasma from rhinoceros whole blood processed within 6 h of collection or stored at 4°C for 24 and 48 h prior to incubation in QFT tubes. Replicate samples of heparinized whole blood from seven subadult male white rhinoceros were used. Results showed no change in IFN-γ levels in unstimulated samples, however the relative concentrations of IFN-γ (based on optical density values) in mitogen plasma decreased significantly with increased time blood was stored post-collection and prior to QFT stimulation. These findings support a need for same-day processing of rhinoceros blood samples for QFT-IGRA testing as per the current practice. Further investigation using TB-antigen stimulated samples is warranted to properly assess the impact of blood storage on TB test results in rhinoceros.

Neuroleptic Malignant Syndrome Secondary to Quetiapine in Critical Care: A Case Report

Quetiapine, an atypical antipsychotic, is widely used to treat delirium in intensive care units (ICUs). Studies demonstrate its efficacy and favorable safety profile. We report a case of an elderly patient who developed clinical and biochemical evidence of neuroleptic malignant syndrome (NMS) 5 days after quetiapine was commenced. Signs of NMS resolved after discontinuation of quetiapine and administration of dantrolene. Quetiapine-induced NMS has occurred with long-term use in the elderly in the outpatient setting. However, NMS has not previously been reported after treatment of ICU delirium. NMS is an important complication to consider before prescribing quetiapine in the ICU.

Patterns of emergency ambulance use, 2009-13: a comparison of older people living in Residential Aged Care Facilities and the Community

OBJECTIVE

to examine demand for emergency ambulances by older people.

DESIGN

retrospective cohort study using secondary analysis of routinely collected clinical and administrative data from Ambulance Victoria, and population data from the Australian Bureau of Statistics and the Australian Institute of Health and Welfare.

SETTING

Victoria, Australia.

PARTICIPANTS

people aged 65 years and over, living in Residential Aged Care Facilities (RACF) and the community, attended by emergency ambulance paramedics, 2009-13.

MAIN OUTCOME MEASURES

rates of emergency ambulance attendance.

RESULTS

older people living in RACF experienced high rates of emergency ambulance attendance, up to four times those for age- and sex-matched people living in the community. Rates remained constant during the study period equating to a consistent, 1.45% average annual increase in absolute demand. Rates peak among the 80-84-year group where the number of attendances equates to greater than one for every RACF-dwelling person each year. Increased demand was associated with winter months, increasing age and being male.

CONCLUSION

these data provide strong evidence of high rates of emergency ambulance use by people aged 65 years and over living in RACF. These results demonstrate a clear relationship between increased rate of ambulance use among this vulnerable group of older Australians and residence, sex, age and season. Overall, absolute demand continues to increase each year adding to strain on health resources. Additional research is needed to elucidate individual characteristics, illness and health system contributors to ambulance use to inform strategies to appropriately reduce demand.

Reducing pre-operative length of stay for enterocutaneous fistula repair with a multi-disciplinary approach

Pre-operative assessment of complex surgical patients can be a lengthy process, albeit essential to minimise complication rates. In a tertiary referral unit specialising in the surgical repair of entercutaneous fistulas, a baseline audit revealed an average in-patient length of stay of 30.1 days, mainly caused by poor co-ordination between specialities. After the introduction of a weekly multi-disciplinary team meeting and the formalisation of a patient pathway, this admission length was reduced to 5.7 days (p<0.01), resulting in significant savings to the department.

Potential organ donor audit in Ireland

As increasing demand for organs is a challenge for transplant services worldwide it is essential to audit the process of organ donation. To address this, a national audit of potential organ donors was undertaken across hospitals with Intensive Care Units (N = 36). Questionnaires were returned on all patients (n = 2073) who died in these units from 1/9/07-31/8/08; 200 (10%) of these patients were considered for Brain Stem Testing (BST), 158 patients (79%) were diagnosed Brain Stem Dead (BSD) and 138 patients (87%) became potential donors. Consent for donation was given by 92 (69%) next of kin and 90 potential donors (65%) became organ donors. There was no evidence of a large number of potential organ donors being missed. Recommendations included completion of BSTs on all appropriate patients, development of support on BST, referral of all BSD patients to the Organ Procurement Service; enhanced co-ordination within hospitals and sustained information/education campaigns.

Analysis of Primary Breast Tumour Stromal Cells and Their Potential Role in Disease Progression

It has emerged in recent years that interaction between breast cancer stromal and epithelial cells supports tumour progression through promotion of epithelial cell growth, migration and invasion. Although this is thought to be mediated through both secretion of paracrine factors and cell-cell contact, the precise mechanisms are poorly understood. The aim of this study was to further characterise stromal cells derived from primary breast tumours and potentially elucidate mechanisms through which they exert their action.Following written informed consent, specimens of human breast cancer were harvested from patients undergoing surgery. Cells were isolated from tumour (n=19) and tumour-associated normal (TAN, n=9) regions of breast tissue. Breast tissue obtained from reduction mammoplasty served as normal controls. Following tissue dissociation and digestion, stromal cells were isolated by differential centrifugation. Following culture of stromal cells, RNA was extracted, reverse transcribed and relative quantitative PCR performed using primers targeting Fibroblast Activation Protein (FAP), Transforming Growth Factor β (TGFβ), Transforming Growth Factor β Receptor II (TGFβRII), Matrix Metalloproteinase 3 (MMP3), and Vascular Endothelial Growth Factor A (VEGF A).There was a trend towards increased expression of VEGF A, TGFβRII and MMP3 in tumour compared to normal stromal cells, while the level of TGFβ expression was equivalent in all samples examined. There was a significant positive correlation between expression of the proangiogenic factor VEGF A and TGFβRII (Pearson correlation coefficient r=0.317, p&lt;0.05). There was also a significant positive correlation between expression of FAP and TGFβRII (r=0.404, p&lt;0.05).Tumour stromal cells have the potential to stimulate angiogenesis through secretion of paracrine factors such as VEGF. This proangiogenic factor is a known target of the TGFb signalling pathway. The elevated level of TGFβRII observed in this study may support TGFβ mediated upregulation of VEGF and thus promote tumour angiogenesis. Further characterisation of stromal cells and their impact on epithelial cell genotype and phenotype is critical to identify targets to inhibit initiation of the metastatic cascade.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 4163.

Prevalences and correlates of non-viral injecting-related injuries and diseases in a convenience sample of Australian injecting drug users

BACKGROUND

The prevalences and correlates of non-viral injecting-related injuries and diseases (IRIDs) in Australian injecting drug users (IDUs) remain unknown.

METHODS

A cross-sectional survey of IDUs was conducted in six sites across Australia's eastern states to investigate IRID experience among Australian IDU. Correlates of IRIDs were explored using logistic and negative binomial regression analyses.

RESULTS

393 IDUs were recruited. Lifetime experience of non-serious IRIDs was common (e.g., 'dirty hit' 68%); potentially serious and serious IRIDs were less commonly experienced (e.g., abscess 16%; gangrene <1%). Factors independently associated with potentially serious or serious IRIDs in the previous 12 months were: injecting in sites other than arms (Adjusted Odds Ratio 3.0, 95% confidence interval 1.7-5.4), injecting non-powder drug forms (5.0, 2.2-11.2), unstable accommodation (2.0, 1.1-3.5), being aged 25 years or older (4.3, 1.7-10.6) and not always washing hands before injection (9.3, 2.1-41.8). Factors independently associated with multiple IRIDs in the preceding 12 months were using three or more injecting sites (Adjusted Incidence Rate Ratio 1.5, 95% CI 1.1-2.0), injecting in sites other than arms (1.7, 1.3-2.2), using non-powder drug forms (1.9, 1.4-2.5), injecting daily or more often (1.7, 1.3-2.2), current pharmacotherapy experience (1.5, 1.1-1.9), and not always washing hands before injecting (1.9, 1.2-2.9).

DISCUSSION

Some IRIDs are widespread among Australian IDUs. Observed associations, particularly the protective effect of handwashing, have useful public health implications.

Addition of a macrolide to a ß-lactam in bacteremic pneumococcal pneumonia

In the study presented here, data collected prospectively from 340 adult patients hospitalised in five countries with bacteremic pneumococcal CAP and treated with a ss-lactam +/- a macrolide were analysed retrospectively to evaluate the efficacy of this antimicrobial combination. Univariate and multivariate analyses revealed no significant effect on case fatality rate when a macrolide/ss-lactam regimen was used as initial therapy. Results were not affected by severity of illness, or by excluding patients who died within 2 days of admission. Identified predictors of death in a multivariate regression model were age >65 years (OR=2.6), two or more lung lobes affected (OR=2.2), and severity of disease as estimated using the acute physiology score (APS)>8.

Audit of Mobile Intensive Care Ambulance Service

The transfer of critically ill patients between hospitals carries significant risk. The Mobile Intensive Care Ambulance Service (MICAS) in Ireland was established in 1996 to provide a ground transfer service between hospitals for critically ill patients. The aim of this audit was to determine if a centralised retrieval system for interhospital transport of critically ill patients in Ireland by MICAS is safe and efficient. 484 critically ill patients transported by MICAS between April 1996 and December 2004 were studied retrospectively. There were no patient deaths during transfer. 47% of transfers were between hospitals in the greater Dublin area. 45% were from regional centres to Dublin. 93% of patients required airway intervention before transfer (intubation or tracheostomy) and 32% needed inotropic support during transfer. The MICAS data confirm the demand for interhospital transport of critically ill patients and suggest that transfer using a centralised retrieval system is safe.

Benchmarking outcome in ICU

There are as yet few well developed systems for comparing the quality of care in Irish hospitals with other hospitals either nationally or internationally. The best known are the perinatal mortality rates of the Dublin maternity hospitals. Other examples include mortality rates after cardiac surgery and survival rates after cancer surgery. We describe a comparison of outcomes in an Irish ICU with internationally validated mortality rates for a given severity of illness. The method of stratifying for severity of illness is by use of the APACHE II scoring system. In 2003 the standardised mortality ratio for Beaumont Hospital ICU was 0.87 with a mean APACHE II admission score of 17.5 which compares favourably with similar data produced from UK units.

Brain death and organ donation: an audit in the Irish National Transplantation and Neurosurgical Centre

We set out to identify the reasons why potential organ donors (PODs) fail to become actual donors and the causes of under-utilization of organs offered for donation. We audited 354 patients who died in the intensive Care Unit over 18 months. Of 155 PODs, 78 (50%) did not undergo brain stem testing (BST) because of (i) unavoidable death from non-CNS causes before BST (n = 50), (ii) treatment withdrawal without BST (n = 17) and (iii) preconditions for BST were not fulfilled (n = 11). Brain death was confirmed in 75 patients. Relatives refused consent for donation in 25 patients organ donation was not discussed with the family in 6, and medical contraindications to organ donation prevented donation in 5. Thirty seven (24% of all PODs) became organ donors who provided a total of 216 organ. All donated kidneys were utilized but unsuitability and logistic issues prevented utilization of 20% and 13% of all donated organs respectively. The commonest reason for failure to utilise potential organ donors was failure to perform BST. In most cases this was because BSTs were not possible but more aggressive management of and the routine performance of BST in all PODs could increase the number of donors. Not approaching relatives to ask consent for organ donation and a high rate of refusal by relatives also led to loss of organ donors.

For love or money? An exploratory study of why injecting drug users participate in research

AIMS

To examine injecting drug user (IDU) motivations as research participants.

DESIGN

Convenience sampling facilitated by recruitment notices distributed through needle and syringe programmes (NSPs), and snowballing within peer networks.

SETTING

NSPs in six suburbs throughout the Melbourne metropolitan area.

PARTICIPANTS

One hundred and fifty-four current IDUs. The mean age was 28 years, 62% were male, and 80% nominated heroin as preferred drug.

MEASUREMENTS

Interviewer-administered survey including questions about socio-demographics, drug use and main reasons for participating in research.

FINDINGS

IDU research participation reasons were consistent with motivational themes such as economic gain (46%), expression of citizenship (38%), altruism (19%), personal satisfaction (17%), drug user activism (16%) and seeking information or assistance (5%). Most respondents (58%) cited reasons where the primary beneficiaries of participation were other individuals or groups (citizenship, altruism, drug user activism) or both self and others.

CONCLUSIONS

IDU motivations for research involvement appear to be multi-dimensional, rarely motivated by economic gain alone, and not necessarily defined by direct benefits or gains to themselves. These findings are relevant to the question of IDU research payment ethics.

Nurse practitioners: an evaluation of the extended role of nurses at the Kirketon Road Centre in Sydney, Australia

The aim of the present study was to formally evaluate the effectiveness, professional appropriateness and acceptability of the extended role of the nurse practitioner at the Kirketon Road Centre (KRC) in Sydney, Australia. Data collection consisted of client and staff surveys and case file review by two assessors (one medical and one nursing). This paper will report on one section of this research, namely the case file review section of the study. Total study subjects were 1046 'at risk' youth, sex workers and injecting drug users attending KRC for their primary health care needs between September 1994 and April 1995. Nurse practitioners (NP) saw 613 of the clients who presented over this period. The majority of these clients were women (77.3%). The majority of NP consults were related to STD (51%), gynaecological (17%) and hepatitis (16%) issues. The results demonstrated that nurse practitioners were professionally appropriate in all aspects of expected 'best practice' in over 95% of consultations.

Prospective study of prognostic factors in community-acquired bacteremic pneumococcal disease in 5 countries

To define the influence of prognostic factors in patients with community-acquired pneumococcal bacteremia, a 2-year prospective study was performed in 5 centers in Canada, the United States, the United Kingdom, Spain, and Sweden. By multivariate analysis, the independent predictors of death among the 460 patients were age >65 years (odds ratio [OR], 2.2), living in a nursing home (OR, 2.8), presence of chronic pulmonary disease (OR, 2.5), high acute physiology score (OR for scores 9-14, 7.6; for scores 15-17, 22; and for scores >17, 41), and need for mechanical ventilation (OR, 4.4). Of patients with meningitis, 26% died. Of patients with pneumonia without meningitis, 19% of those with >/=2 lobes and 7% of those with only 1 lobe involved (P=.0016) died. The case-fatality rate differed significantly among the centers: 20% in the United States and Spain, 13% in the United Kingdom, 8% in Sweden, and 6% in Canada. Differences of disease severity and of frequencies and impact of underlying chronic conditions were factors of probable importance for different outcomes.

Tissue iodine content and serum-mediated 125I uptake-blocking activity in breast cancer

In the thyroid, active transport of iodide is under control of the TSH-dependent Na+/I- symporter (NIS), whereas in the breast such control is less well understood. In this study, NIS expression was demonstrated by RT-PCR in 2 of 2 fibroadenomata and 6 of 7 breast carcinoma messenger ribonucleic acid isolates. In addition, mean total tissue iodine levels of 80.9 +/- 9.5 ng I/mg protein in 23 benign tumors (fibroadenomata) were significantly higher than those in 19 breast cancers taken from either the tumor (18.2 +/- 4.6 ng I/mg) or morphologically normal tissue taken from within the tumor-bearing breast (31.8 +/- 4.9 ng I/mg; P < 0.05 in each case). Inhibition of 125I uptake into NIS-transfected CHO cells was observed in serum from 20 of 105 (19.0%) breast carcinoma, 8 of 49 (16.3%) benign breast disease, and 27 of 86 (31.4%) Graves' patients, but in only 1 of 33 (3.0%) age-matched female controls. IgG purified from serum of patients showing positive 125I uptake inhibition also inhibited iodide uptake, suggesting that such inhibition was antibody mediated. 125I uptake inhibition was significantly associated with thyroid peroxidase antibody positivity (P < 0.05) in sera from breast cancer patients, but not in those with benign breast disease, once again suggesting an association between thyroid autoimmunity and breast carcinoma.

Early experience in the use of Levovist ultrasound contrast in the evaluation of liver masses

The aim of the present paper was to assess the utility of Levovist in defining the pathology of liver masses. Levovist is a new ultrasound contrast agent consisting of galactose microparticles, air bubbles and palmitic acid. Prospective studies were performed in patients referred for further evaluation of known liver masses. Levovist was peripherally injected and colour Doppler ultrasound studies were performed. Findings were correlated with clinicopathology and three other imaging modalities: biphasic spiral CT, CT arterial portography and contrast MRI. Twenty-five patients were studied (15 male and 10 female) in the age range 25-74 years. Liver masses ranged from 0.5 to 7 cm in maximum diameter. Thirteen lesions were benign and 12 were malignant (four hepatomas (HCC) and eight metastases). Levovist enhancement occurred in 18 lesions. Of these, six were benign (four focal nodular hyperplasias (FNH) and two haemangiomas). All 12 malignant lesions demonstrated enhancement. The HCC showed a mosaic pattern of central and peripheral enhancement, and the FNH demonstrated a spoke-wheel pattern. It was not possible to distinguish between haemangiomas and malignant lesions. Non-enhancing lesions may well be benign, with all malignancies showing some enhancement. Characteristic enhancement patterns were found for HCC (mosaic) and FNH (spoke-wheel). It was not possible to distinguish between metastases and benign lesions (haemangiomas) when the pattern of enhancement was peripheral.

Infection with HIV and hepatitis C virus among injecting drug users in a prevention setting: retrospective cohort study

OBJECTIVES

To estimate the incidence of HIV and hepatitis C virus and risk factors for seroconversion among a cohort of injecting drug users.

DESIGN

Retrospective cohort study.

SETTING

Primary healthcare facility in central Sydney.

SUBJECTS

Injecting drug users tested for HIV-1 antibody (n=1179) and antibodies to hepatitis C virus (n=1078) from February 1992 to October 1995.

MAIN OUTCOME MEASURES

Incidence of HIV-1 and hepatitis C virus among seronegative subjects who injected drugs and underwent repeat testing. Demographic and behavioural risk factors for hepatitis seroconversion.

RESULTS

Incidence of HIV-1 among 426 initially seronegative injecting drug users was 0.17/100 person years (two seroconversions) compared with an incidence of hepatitis C virus of 20.9/100 person years (31 seroconversions) among 152 injecting drug users initially negative for hepatitis C virus. Incidence of hepatitis C virus among injecting drug users aged less than 20 years was 75.6/100 person years. Independent risk factors for hepatitis C virus seroconversion were age less than 20 years and a history of imprisonment.

CONCLUSIONS

In a setting where prevention measures have contributed to the maintenance of low prevalence and incidence of HIV-1, transmission of hepatitis C virus continues at extremely high levels, particularly among young injecting drug users.

Diffuse panbronchiolitis: case report and review of the literature

Diffuse panbronchiolitis is an uncommon disease of unknown aetiology mainly occurring in Asian races. Treatment with erythromycin acting through unclarified mechanisms is promising and may improve the poor prognosis currently associated with the disease. A case is presented illustrating how the imaging features of the disease, particularly on high-resolution computed tomography, may be used to support a diagnosis suggested on clinical grounds.

Viridans streptococci in blood cultures. Can we see any patterns of species related to patient category? Review of 229 cases of positive cultures with viridans streptococci

We present a review of 229 blood cultures with viridans streptococci collected during a period of eight and a half years from 1986 to 1994 at a teaching hospital in Sweden. The clinical significance of the growth of viridans streptococci is always uncertain, since these bacteria can be contaminants from the skin flora. Growth in more than one culture bottle strengthens the clinical value of the finding. The question was whether species identification might also help in the assessment of the clinical relevance of the finding. The results show that Streptococcus mitis occurs significantly more frequently in blood cultures from the departments dealing with cancer patients. Even with polymicrobial growth in blood cultures, S. mitis should be considered a pathogen of clinical relevance, not a contaminant.

Lymphomatoid granulomatosis: case report and review of the literature

Lymphomatoid granulomatosis (LG) is an uncommon disease now regarded by most authors as an unusual form of lymphoma with the ability to affect any bodily system. The disease and its complications may result in a spectrum of radiological appearances. A case illustrating how cerebral lesions may mimic demyelinating plaque, neoplasm or infection and how pulmonary lesions may lead to pneumopericardium is presented. The difficulty in establishing a definitive diagnosis, due to the non-specificity of symptoms, pathological investigations and radiological appearances of the disease, is emphasized. Clinicians must therefore consider LG in their differential diagnoses, as delayed treatment may affect prognosis.

Peripheral blood flow in the elderly during inhalational anaesthesia

We investigated whether aging altered the peripheral vascular effects of inhaled anaesthetic agents. Forearm blood flow (FBF) was measured in 20 young (18-34 yrs) and 21 healthy elderly (60-79) patients receiving isoflurane or halothane with 66% nitrous oxide (N2O) in oxygen (O2). After etomidate 0.3 mg/kg and vecuronium 0.1 mg/kg, the trachea was intubated and controlled ventilation instituted with 66% N2O in O2. Halothane or isoflurane were administered to achieve end-tidal concentrations of 0.5% halothane or 0.9% isoflurane after 20 min. FBF was measured by venous occlusion plethysmography during the 20 min study period. Induction of anaesthesia with etomidate decreased FBF below baseline (awake) values in both elderly and young; intubation returned FBF to baseline values in the young but not in the elderly. FBF decreased below baseline values in young and elderly patients receiving halothane and in elderly patients receiving isoflurane but not in young patients receiving isoflurane. FBF was significantly greater in young patients receiving isoflurane than halothane after 20 min administration. We conclude that perfusion of forearm muscle and skin is maintained in the young but not in the elderly during anaesthesia with isoflurane/N2O. Perfusion of forearm muscle and skin decreases in both young and elderly patients during anaesthesia with halothane/N2O. The cardiovascular effects of isoflurane/N2O and halothane/N2O did not differ significantly in healthy elderly patients.

Uptake of halothane and isoflurane by mother and baby during caesarean section

Twenty-three patients undergoing Caesarean section received either 0.5% halothane or 0.8% isoflurane to supplement nitrous oxide-oxygen anaesthesia. We studied the rate of uptake of the agents by the mother and fetus by measuring partial pressures in maternal arterial (Pa) and fetal umbilical venous (Puv) blood. Mean induction-delivery interval did not differ between the halothane (10.8 min) and isoflurane (11.7 min) groups. There were no differences in maternal heart rate, arterial pressure, pH and blood-gas tensions and fetal pH, blood-gas tensions or Apgar scores between the two groups. Isoflurane uptake by the mother was more rapid than halothane; at delivery, mean Pa of isoflurane as a fraction of the inspired partial pressure (Pl) was 0.44 compared with 0.35 for halothane (P < 0.05). Mean Puv as a fraction of maternal Pa at delivery was 0.71 for both agents; thus placental transfer was the same for both agents. Consequently mean Puv/Pl was greater for isoflurane (0.32) than halothane (0.26) (P < 0.05). We conclude that both halothane and isoflurane are suitable agents for general anaesthesia for Caesarean section. The rate of uptake of isoflurane by the mother during Caesarean section was more rapid than halothane. The rate of uptake by the fetus from the mother was the same for halothane and isoflurane, so that fetal partial pressure as a fraction of the inspired partial pressure was greater for isoflurane than halothane.

A comparison of HIV risk between women and men who inject drugs

Although there is growing evidence of differences between women and men who inject drugs (IDUs) in terms of level of risk for HIV infection, very little research has been conducted specifically addressing the risk practices of women IDUs. This study formed part of a national study of HIV infection risks in IDUs and the purpose of the present analysis was an exploration of gender differences in HIV risk practices, focusing on the HIV risk practices of IDU women. 1,245 IDUs from the inner city area of Sydney took part in this study. Of these, 908 were men and 331 were women. Notable results were that female respondents were more likely to report sharing needles, they injected heroin more times in a typical using month and were more likely to have shared with someone they later found out was HIV seropositive. Female respondents also reported more sexual partners than men, were more likely to engage in prostitution, and were more likely to have sexual partners who were themselves IDUs. The results provide support for the proposition that women who inject drugs may be at greater risk of HIV infection through both their drug taking and their sexual practices. Further research is needed to explore the reasons underlying the risk practices of women who inject drugs and an understanding of these factors needs to be incorporated into HIV risk-reduction and drug harm-reduction policies and programs.

Effects of isoflurane and nitrous oxide in subanesthetic concentrations on memory and responsiveness in volunteers

Awareness, defined as conscious memory during anesthesia, has been a problem in anesthesia practice. To determine the effect of isoflurane and nitrous oxide (N2O) on memory, 17 healthy adult volunteers were randomly assigned to receive isoflurane or N2O and received the alternate agent 1-2 weeks later. Each volunteer was studied at four end-tidal concentrations of each agent, consecutively 0.15, 0.3, 0.45, and 0.15 times the minimum alveolar concentration (MAC) for isoflurane or 0.3, 0.45, 0.6, and 0.3 times MAC for N2O. After 15-min equilibration at each end-tidal concentration, volunteers were tested for voluntary response to command and were presented with verbal information to be recalled after anesthesia. Volunteers were interviewed on the day after the study and tested for conscious and unconscious memory of the information presented during anesthetic administration. MAC-awake (the end-tidal concentration preventing voluntary response in 50% of volunteers) was 0.38 (0.35-0.42) times MAC for isoflurane and 0.64 (0.61-0.68) MAC for N2O (means, 95% confidence limits), indicating isoflurane to be more potent than N2O in suppressing voluntary response (P = .0001). Memory data were analyzed in 12 volunteers who completed the study and in whom the allocation of information to be recalled was counterbalanced among agents and concentrations of agents. Memory was decreased by increasing concentrations of both agents. Conscious memory of the information presented during anesthetic administration was prevented by 0.45 MAC isoflurane but not completely prevented by 0.6 MAC N2O. Unconscious memory (defined as memory of information without conscious recognition) occurred during administration of both agents and was prevented by 0.45 MAC isoflurane but not by 0.6 MAC N2O. Isoflurane was more potent in suppressing memory than MAC-equivalent concentrations of N2O. Using models of the relationship between dose of agent and suppression of memory, a dose of both agents was estimated that suppressed memory by 50% (ED50). The ED50 was 0.20 MAC for isoflurane (95% confidence intervals, 0.15-0.25), and 0.50 MAC for N2O (95% confidence intervals 0.43-0.55). We conclude that isoflurane and N2O suppress memory in a dose-dependent manner, and that isoflurane is more potent in preventing memory and voluntary response to command than MAC-equivalent concentrations of N2O.

Isoflurane anesthesia prevents unconscious learning

We investigated whether greater than or equal to 0.6 minimum alveolar concentration (MAC) of isoflurane suppresses learning of information presented verbally. Preoperatively, we asked 45 healthy patients (aged 23-58 yr) undergoing elective surgery 15 general knowledge questions designed to arouse their curiosity. They were told that they would be given the answers during anesthesia. Anesthesia was induced with isoflurane and nitrous oxide (25 subjects also received 1.1 +/- 0.6 mg/kg of propofol). The trachea was intubated with the aid of vecuronium (0.07 mg/kg IV). Isoflurane in oxygen was given to provide 0.6 MAC before and 1.0 and 1.4 MAC during surgery. After 10 min at each of two of the three MAC levels, the answers were given to five of the questions. At the remaining concentration, patients received a message to either touch an ear (n = 30) or keep their arms still (n = 15) during the postoperative interview. Twenty-four hours later, patients were asked whether they recalled intraoperative events. They were then asked to answer the 15 questions, choosing from five possible answers to each, one of which was correct. The number of times each patient touched an ear during this interview was noted. No patient consciously recalled events during anesthesia. The number of questions answered correctly postoperatively did not differ according to whether the answers had been provided during anesthesia (at any isoflurane concentration) or had not been provided (control questions). The number of ear-touches postoperatively did not differ between those who had and had not received the intraoperative message encouraging ear-touching.(ABSTRACT TRUNCATED AT 250 WORDS)

Visceral losses of desflurane, isoflurane, and halothane in swine

Percutaneous loss of inhaled anesthetics is small relative to their uptake. The minor nature of this loss results in part from the substantial barrier to diffusion posed by the skin. Pleural and peritoneal surfaces pose less effective barriers because diffusion distances are smaller than in the skin. Accordingly, we measured visceral loss to air of desflurane, isoflurane, and halothane from pleural and peritoneal surfaces in five juvenile swine. Pleural and peritoneal losses per percent end-tidal anesthetic correlated directly with the solubility of the anesthetic in blood or tissues. The total pleural losses for the first 30 min of anesthetic administration were desflurane, 1.22 +/- 0.22 mL (mean +/- standard deviation for the 30-min period); isoflurane, 2.34 +/- 0.52 mL; and halothane, 4.69 +/- 0.98 mL; respective peritoneal losses were 0.64 +/- 0.12 mL, 1.23 +/- 0.25 mL, and 2.69 +/- 0.57 mL. Pleural loss per unit time did not change with increasing duration of anesthesia, whereas peritoneal loss increased for all anesthetics. These visceral losses are greater than total percutaneous losses in humans given these anesthetics for the same period of time, but the loss of anesthetic by either route is too small to affect measurements of anesthetic kinetics or recovery.

End-tidal concentrations of halothane and isoflurane during induction of anaesthesia in young and elderly patients

Twenty-two young (18-32 yr) and 22 healthy elderly (60-80 yr) patients received either halothane or isoflurane for maintenance of anaesthesia during controlled ventilation. End-tidal fractional concentrations (FE) of the agents were measured for 20 min after their introduction into inspired gas and the increase in end-tidal concentrations of the two agents was compared during induction of anaesthesia using the ratios of FE to the inspired fraction (FI). FE:FI ratios for isoflurane were higher than those for halothane in both young and elderly patients, confirming that equilibration of end-tidal with inspired concentration occurs more rapidly with isoflurane than with halothane in both age groups. FE:FI ratios for isoflurane became significantly lower in the elderly than in the young after 15 min administration of isoflurane. This suggests slower induction of anaesthesia in the elderly if equipotent concentrations of isoflurane are used; the clinical significance of this difference is probably small. Mean FE:FI ratios for halothane in elderly patients were similar to those in the young throughout induction of anaesthesia.

A vasculopathy with deposition of lambda light chain crystals

An 82-year-old man and a 34-year-old woman developed subacute, obstructive, fatal vasculopathies characterized by extensive crystalline tissue deposits and monoclonal lambda light chain serum components. Cryocrystalglobulinemia was also present in one patient, and the purified crystals contained only lambda light chain dimers. Although the presentation of these patients resembled that of systemic necrotizing vasculitis, histologic evidence of inflammation was lacking and their subsequent rapid clinical deterioration was not altered by corticosteroid therapy, and in one case cyclophosphamide and plasmapheresis. Both patients died within 3 weeks of presentation.

Comparison of plasma bupivacaine concentrations during continuous extradural infusion for labour

Twenty patients who requested extradural analgesia for labour were allocated randomly to receive an infusion of either 0.25% or 0.08% solutions of bupivacaine. Following an initial bolus dose of 50 mg, the infusions were given at a rate of 20 mg h-1. Both solutions provided acceptable pain relief, but plasma concentrations were significantly lower with the weaker concentration.